SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '884e8e02b91fbcc2587437ccf4121f9bc0d5688d7451625a43bcffb99468abe3' 
  AND token = 'Z8eJqoEXVm8/Y6OL45wswmJY6FhUbq6GQtfNHZ1AVjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}